Many children who have had strokes in the perinatal period develop normal or near-normal linguistic abilities. Consequently, these children should serve as an excellent model system for studying developmental plasticity using functional MRI (fMRI). This exploratory project is designed to develop a substrate for an extensive and long-term fMRI-based investigation of children with perinatal stroke. The following specific aims are proposed: Aim 1: To explore the feasibility and validity of using current fMRI methodologies in normal children. Methods for the characterization of brain activity have been developed over several years for use in normal and abnormal adult populations. Whereas some of these methods might be straightforwardly applied to children, others are less obviously generalizable. Studies in Aim1 will assess and develop methodologies for fMRI studies in normal children and children with perinatal stroke. Aim 2: To begin studies, in normal children, of behavioral profiles and associated brain activation patterns using previously characterized language tasks. Tasks and fMRI protocols, similar to those previously employed in adult studies of the processing of single words, will be tested and modified. Initially, children ages 7-10 will be studied. These experiments will also be extended to a small group of children ages 3-6 to identify problems specifically associated with studying this younger age group. Aim 3: To explore the feasibility of using language tasks developed in Aim 2 for the study o f the relationship of perinatal lesion to behavioral profiles and patterns of brain activation. Studies successfully implemented in Aim 2 will then be performed on children ages 7-10 who, despite enduring a focal unilateral stroke in the perinatal period, do not manifest significant cognitive or linguistic sequelae. Aim 4: To begin development of new sets of tasks that address aspects of language more broadly. The tasks that have been used in many functional neuroimaging experiments, including ours, have tended to focus on the phonology and semantics of single words. Preliminary studies of single words. Preliminary studies of syntactic processes, including grammatical morphology and syntactic comprehension, will be initiated in normal adults and normal children.